JPH01230737A - Member made of composite material and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a composite material, and more particularly to a member made of a composite material and a method for manufacturing the same.

2. Prior Art In order to reduce the weight of parts that have traditionally been made of metal materials such as steel, attempts have been made to make them from composite materials that have a matrix of light alloys and reinforcement materials such as ceramic fibers. It is being carried out vigorously. For example, JP-A-59
JP-A-226140 and JP-A-61-143535 disclose valves for internal combustion engines made of such composite materials.

Problems to be Solved by the Invention If members are made of such composite materials, they can be made lighter than those made of steel, but depending on the usage conditions, the parts or Excessive wear may occur on the mating materials, or sufficient durability may not be ensured. For example, valves for internal combustion engines are used under extremely harsh conditions such as high temperatures and no lubrication, so if the volume fraction of the reinforcing material is low, adhesive wear will occur on the valve face; If is high, abrasive wear will occur on the valve seat.

Furthermore, since the heat resistance of composite materials having a matrix of light alloys is generally lower than that of steel, etc., breakage is likely to occur in the bulb head portion of the valve, which is exposed to adverse conditions of high temperature and high stress. If the volume fraction of the reinforcing material is set high to avoid such breakage, machinability and plastic deformability will be significantly reduced, which will not only worsen productivity but also reduce the toughness of the valve. It becomes impossible to withstand the impact stress when sitting.

In view of the above-mentioned problems with conventional composite material parts that use a light alloy as a matrix and ceramic fibers as reinforcement materials, the present invention has been developed to provide a material that can be used even when specific parts are exposed to severe usage conditions. The purpose of the present invention is to provide a composite material member that has been improved to ensure sufficient durability and has excellent productivity, and also provides a manufacturing method that allows such a member to be efficiently manufactured in a low position. It is intended to.

Means for Solving the Problems According to the present invention, the object as described above is achieved by providing a member made of a composite material having a light alloy as a matrix and ceramic fibers or ceramic particles as a reinforcing material, and incorporating the above into the matrix in a specific portion. A method for producing a composite material member in which an intermetallic compound of a metal element as the main component of the matrix and another metal element is finely dispersed, and a composite material member in which a light alloy is used as a matrix and ceramic fibers or ceramic particles are used as a reinforcing material. to form a reinforcing material molded body made of ceramic fibers or ceramic particles in which particles containing a metal element that reacts with the main component metal element of the matrix to form an intermetallic compound are dispersed in specific parts, and This is achieved by a method for manufacturing a composite material member that includes infiltrating a molten metal of the matrix into a molded material.

Effects and Effects of the Invention According to the composite material member of the present invention, intermetallic compounds of the main component metal element of the matrix and other metal elements are finely dispersed in the matrix in a specific portion. As described in detail in Japanese Patent Application No. 1983 filed on the same date as the present applicant, the wear resistance and heat resistance of composite materials are improved by intermetallic compounds. Therefore, the durability of components used under extremely severe conditions, such as valves for internal combustion engines, can be greatly improved. In addition, since there is no need to set the volume fraction of the reinforcing material high, there is no need to cause excessive wear on the mating material or significantly reduce machinability or plastic deformability, so the volume fraction of the reinforcing material is set high. It is possible to improve the productivity of the member compared to the case where it is used, and furthermore, it is possible to avoid a decrease in the toughness of a specific portion, so that the durability of the member can also be improved.

Further, according to the manufacturing method of the present invention, a reinforcing material molded body made of ceramic fibers or ceramic particles in which particles containing a metal element that reacts with the main component metal element of the matrix to form an intermetallic compound are dispersed in a specific part. is formed,
The molten metal of the matrix is infiltrated into the reinforcing material molded body. Therefore, a composite material is formed by the molten metal of the matrix permeating into the compact, and at the same time, the particles in the compact react with the main component metal elements of the matrix, creating intermetallic compounds finely dispersed in the matrix. It is formed. Therefore, a component made of composite material in which the intermetallic compound is finely dispersed only in the matrix of a substantially specific part of the component can be easily and easily manufactured using a device, and the intermetallic compound can be bonded well with the surrounding matrix. It is possible to produce components made of composite materials that are tightly bonded and have high performance.

According to one detailed feature of the present invention, the composite material member of the present invention is a valve for an internal combustion engine, and the specific portion defines the valve face surface of the umbrella portion and the valve seat contact surface. This is the part to do.

Thus, when the member according to the present invention is applied to a valve for an internal combustion engine, the strength of the valve and the wear resistance of the stem portion can be sufficiently improved if the volume fraction of the reinforcing material is less than 10%. On the contrary, the volume ratio of the reinforcement material is 30%.
Exceeding this will easily cause abrasive wear on the valve stem guide.

Furthermore, if the Vickers hardness of the intermetallic compound is less than 300, it is difficult to effectively prevent adhesive wear on the valve seat contact surface of the cap, and conversely, if the Vickers hardness exceeds 950, the valve seat Abrasive wear becomes more likely to occur. Similarly, if the volume fraction of the intermetallic compound is less than 15%, it is difficult to effectively prevent adhesive wear on the valve seat contact surface, and the strength of the umbrella portion cannot be sufficiently improved. On the other hand, if the volume fraction of the intermetallic compound exceeds 50%, the heat check resistance of the cap portion will deteriorate and hot cracks will easily occur in the cap portion.

According to one detailed feature of the invention, therefore, the volume fraction of the reinforcement is set between 10 and 30%, and the Vickers hardness and volume fraction of the intermetallic compound are set between 300 and 950.15, respectively.
Set to 50%.

The particle size of the intermetallic compound and the particle size of the particles used in the production method of the present invention are preferably about 5 to 40 μm and 12 to 15 μm, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in detail below by way of example embodiments with reference to the accompanying figures.

Embodiment 1 FIG. 1 shows a partially cutaway injection port of an embodiment of a composite material member according to the invention configured as a valve for an internal combustion engine, and FIGS. 2 to 6 show an injection port according to the method of the invention. FIG. 2 is a flowchart showing a series of manufacturing steps for manufacturing the valve shown in FIG. 1. FIG.

In FIG. 1, the reference numeral 10 indicates a valve, which includes a stem portion 12 and an umbrella 7 portion 14 formed integrally with the stem portion.
It has The umbrella portion 14 repeatedly engages with a valve seat of a cylinder head of an internal combustion engine (not shown),
It has a valve seat contact surface 16 that selectively opens and closes an intake port or an exhaust port, and a valve face surface 18 that defines a part of the combustion chamber of the internal combustion engine. As shown in the figure, the valve face is made of aluminum alloy 22 (JIS standard A) composite reinforced with silicon carbide whiskers 20.
CIA), and in particular, the matrix in the portion defining the valve seat contact surface 16 and the valve face surface 18 of the umbrella portion 14 contains metals including A1, which is the main component of the matrix, and Nl as another metal element. intermediate compound (Ni A
l 3 , Nl 3 AI) are finely dispersed.

The valve shown in FIG. 1 was manufactured according to the method of the invention as follows.

First, silicon carbide whiskers (average fiber diameter 0.2 μm, average fiber length 50 μff1) are wet-fibrillated, and then
Ni powder of μm was mixed at 25vol% with respect to the whisker. The thus formed mixture of silicon carbide whiskers 20 and Nl powder 28 was then placed in a compression mold 32 with a diameter of 30 ff and a depth of 111%, which has small holes 30 for dewatering in the bottom wall 26, as shown in FIG. It was poured into a cavity 34 with a height of 50 mm to a thickness of 10 mm, and on top of it was poured only wet defibrated silicon carbide whiskers 26 to a thickness of 30 mm. Next, the silicon carbide whiskers and the like are compressed and dehydrated by the upper mold 36 that engages with the mold 32, so that the silicon carbide whiskers etc.
A fiber molded body 38 made of silicon carbide whiskers 20 having a height of 15 + + m and a volume fraction of 20% was formed. In addition, N
1 powder 28 was substantially uniformly dispersed at a volume fraction of about 5%.

Next, the fiber molded body 38 is preheated to 400°C, placed in the mold cavity 44 of the lower die 42 of the pressure casting device 40, and an aluminum alloy (JIS
A molten metal 46 of standard ACIA) is poured and the molten metal is pressurized to a pressure of approximately 1000 kg/c- by a plunger 48, thereby filling the molten aluminum alloy into the fiber molded body and separating A1 in the molten metal and the molded body. The Ni-Al intermetallic compound was formed into a fine Ni-Al intermetallic compound.

Next, a billet made only of the composite material is cut from the obtained casting, and the billet 49 is preheated to 505° C., placed in the cavity 52 of an extrusion device 50 as shown in FIG. 5, and a die 54 is placed against the billet. By pressing and extruding a portion of the billet through the hole, a valve blank as shown in FIG. 6 was formed. Next, the valve blank material was subjected to mechanical processing such as grinding, thereby forming a valve as shown in FIG. In addition, N l of the part that defines the valve face surface and the part that defines the valve seat contact surface.
-AI intermetallic compounds (Ni At 3 , Ni 3A
The volume percentage of +) was about 31%.

The thus obtained valve was installed in a 4-cylinder 2000 cc gasoline engine and a durability test was conducted at full load and 6000 rpm, and it was found that this valve had good durability.

For the purpose of comparison, a bulb was formed using the same procedure and conditions as in the above example except that Nl powder was not used, and a durability test was conducted on the bulb under the same procedure and conditions. However, 30 hours after the start of the test, excessive wear occurred on the valve seat contact surface of the valve, and blow-through occurred.

Example 2 A valve for an internal combustion engine having the specifications shown in Table 1 below was formed in the same manner as in Example 1 above, and a durability test was conducted in the same manner and under the same conditions as in Example 1. went. The reinforcing material used was the same silicon carbide whisker as in Example 1.

As a result, relatively large wear occurred on the stem portion of valve A, cracks appeared on the cap portion of valve D, and valve E
For valves G and J, there was relatively large wear on the valve seat contact surface, for valves G and J, there was relatively large wear on the valve seat, which is the mating material, and for valve K, there was relatively large wear on the valve seat contact surface. Extensive wear occurred. On the other hand, such problems did not occur in valves B, CSF, H, and I, and it was therefore confirmed that these valves had good durability.

Example 3 Alumina short fibers (average fiber diameter 2μ, average fiber length 200
[mu]m) was wet-fibrillated, and Fe powder having an average particle size of 5 [mu]m was mixed therein at 25 vol% based on the fibers, and after stirring the mixture, it was poured into a mold and allowed to stand still. Next, water is sucked and dehydrated from the bottom wall of the mold, and the mixture is further dehydrated by pressurizing with an upper mold that fits into the mold, and the mixture is dried to have dimensions of 3011111° in diameter and 30Ilffl in height.
A fiber molded body was formed in which the volume percentage of short alumina fibers was about 20%. Approximately 5ffiI1 from the lower end of this fiber molded body
1, Fe particles are dispersed at a relatively high content of approximately 5 vol. Approximately 0.
5 vo1%).

The thus formed fiber molded body was then used to form a valve for an internal combustion engine in the same manner and under the same conditions as in Example 1 above, except that the matrix was replaced with an aluminum alloy (JIS standard AC2B). A durability test was then conducted on the valve under the same conditions as in Example 1. As a result, it was found that the valve of this example also had good durability.

Although the present invention has been described above in detail with reference to several embodiments, the present invention is not limited to these embodiments, and various other embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art that

[Brief explanation of the drawing]

FIG. 1 shows a partially cutaway injection port of one embodiment of a composite material member according to the present invention configured as a valve for an internal combustion engine, and FIGS. 2 to 6 show an injection port for the internal combustion engine shown in FIG. FIG. 2 is a flowchart showing a series of manufacturing steps for manufacturing an engine valve according to the method of the present invention. 10... Valve for internal combustion engine, 12... Stem part, 1
4... Umbrella portion, 16... Valve seat contact surface,] 8.
...Valve face surface, 20...Silicon carbide whisker, 22...Aluminum alloy, 24...Intermetallic compound, 26...Bottom wall, 28...N1 powder, 30...
Small hole, 32... Compression mold, 34... Cavity,
36... Upper mold, 38... Fiber molded body, 40... Pressure casting device, 42... Mold, 44... Mold cavity, 46... Molten metal of aluminum alloy, 48...
- Plunger, 49... Billet, 50... Extrusion device, 52... Billet, 54... Die, 56...
...Rough valve material. Patent applicant: Toyota Motor Corporation representative
Patent attorney Masa Akashi
Tsuyoshi 1 Figure 10... Valve 14... All 16... Valve seat contact surface 18... Valve face surface 20... Silicon carbide whisker 22... Aluminum alloy 24... Intermetallic compound Figure 2, 6, 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) A composite material member having a light alloy as a matrix and ceramic fibers or ceramic particles as a reinforcing material, and an intermetallic compound of a main component metal element of the matrix and another metal element in the matrix in a specific part. Composite material member with finely dispersed particles. (2) A method for manufacturing a composite material member using a light alloy as a matrix and ceramic fibers or ceramic particles as a reinforcing material, wherein the particles contain a metal element that reacts with the main component metal element of the matrix to form an intermetallic compound. 1. A method for manufacturing a composite material member, comprising: forming a reinforcing molded body made of ceramic fibers or ceramic particles dispersed in specific portions; and infiltrating the molten metal of the matrix into the reinforcing molded body.